1. Field of the Invention
The invention relates to exercise equipment, more particularly to an elliptical exercise device.
2. Description of the Related Art
FIG. 1 shows a conventional stationary exercise device disclosed in U.S. Pat. No. 5,383,829. The conventional stationary exercise device includes a frame 11, two foot links 12, two coupling members 13, and two guide members, in the form of tracks 14. The frame 11 has a pivot axis defined by a shaft 16 which is supported by the frame 11, and a flywheel 15 supported by the shaft 16 for rotation about the pivot axis. Each coupling member 13 has one end connected pivotally to the shaft 16, and an opposite end connected pivotally to a first end of the corresponding foot link 12. A second end of each foot link 12 is provided with a roller unit 17 operable to slide along a respective one of the tracks 14. When the flywheel 15 is rotated, the coupling members 13 bring the first end of each foot link 12 to travel in a circular path about the pivot axis, while the tracks 14 direct the second end of each foot link 12 in a reciprocal path as the first ends of the foot links 12 travel about the pivot axis.
With reference to FIG. 2, in combination with FIG. 1, when the user places his/her foot on a foot retaining pad 121 of the respective foot link 12 and starts to exercise with his/her foot moving forwardly and consecutively at locations IV, III, II and I, the heel portion of the user's foot rises at a faster rate than the toe portion.
With reference to FIG. 3, when the user's foot moves rearwardly and consecutively at locations I, VI, V and IV, the heel portion of the user's foot lowers at a faster rate than the toe portion.